Automatic control for oil burners



Dec. 28 1926. 1,612,596

l.. S. MARKS AUTOMATIC CONTROL FOR OIL BURNERS Filed Jan. 19, 1923 wvento/o abtozmg LONEL S. MARKS, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO PEABODY ENGI- HEER/ING CORPOBATXON, A CORPORATION OF NEW YORK.

AUTOMTC CONTROL FOR OIL BURNERS.

Application filed January 19, 1923. Serial No. 613,692.

My invention relates to a method of automatically controlling combustion of liquid or other fuel injected into a furnace and mixed with the proper amount of air'for comlmstiou, more particularly to the use of oil fuel injected into a boiler furnace by means ot'v mechanical atomizers of the type which are controlled over a wide range in capacity hy returning a 'portion ofthe oil through a return manifold which may be litted with one control valve., and has for its object the production ot' a simple and sensitive automatic control which regulates the amount of oil burned through the use of variations in steam pressure and at the same time controls the damper or air regulator by the pressure in the by-pass line or return manifold.

During all periods of change of'fuel supply, either increase or decrease, an adequate air supply should be maintained so as to ensure good combustion and the absence of smoke. (lne of the objects of my invention is to produce a system of control that'will accomplish this fac-t.

'l`he foregoing and other features of my invention will now be describedy in connection with the accompanying drawing 1n` which l1 have diagrammatically shown a 30 preferred embodiment after which lt shall point out in the claims those features which l believe to be new and of my own invention.

lu the drawings y Figure 1 is a diagrammatical View of my control system.

Figure 2 is a diagrammatical section of an atomizer to which my control may be applied.

In the diagram, Figure 1, I indicate a Mason regulator 1 or similar device which controls the by-pass Valve 2 and thereby controls the fuel supply. This valve is in the ret-urn manifold 24 of aymeclianical atomizer 20 or group of atomizers. When the Valve 2 is shut off the atomizer 20 Will actas la straight mechanical atomizer, and as the valve 2 1s opened a regulable amount of oil is toy-passed the atomizer tip thereby ,reducing t-he oil entering into the combustion chamber', all of which is common to the Pew body-Fisher burners and system of control and therefore requires no further description here.

Attached 'to the connection 3 interposed between theregulator 1 and the by-pass valve 2 is a dash pot cylinder 4 slidably mounted in guides 4. 'lhe piston 5 connects through a flexible connection 6, with the boiler damper or air control device 7. To the connection 6 is attached another flexible connection or chain 8 which connects with the air control apparatus t). An expansion spring 14 tends to move 'the piston 5 toward the left in the dash pot 4. y

ln the preferred form this apparatus would be a sylphon or metal bellows with hy-pass pressure inside.. This pressure is the same as the pressure of the oil in the return manifold and as the pressure increases the sylphon will expand. One end is held stationary as at 10 and the opposite end 1l is connected through the fiexible connection 8 to the boiler damper control device 7.

rlhe action of this apparatus is as follows z-lith decrease of steam pressure the regulator 1 rotates contra-clockwise, closing the by-pass valve 2 and moving the dash pot 4 to theleft, at the same time carrying with it the dash pot piston and thereby opening the damper through the control device 7. The chain 8 becomes slack. rlfhe weight 12 exerts a constant force on the dash pot piston and moves it to the right tending at the same time to straighten out the exible con-l nection or chain 8. The damper control T finally finds its correct position under the action of the air control apparatus 9, due to the expansion of the sylphon under increasing pressure in the by-pass line.

lVith the increase of steam pressure the 4regulator 1 turns clockwise, the dash pot 4 is drawn to the right by the action of the weights 13 and chain 6 becomes slack. The damper control 7 consequently remains for the time being 'unchanged while the fuel amount is cu't down, then as the by-pass pressure diminishes in sylphon or metal bellows 9 the we'ight'12v will close the air damper...

Referring particularly to Figure 2 in which I have shown diagrammatieally an. a-tomizer to -which my control may be applied, represents an atomizer tip, 21 a whirling or central chamber into which the oil supply 22 is lead tangentially as at 23.` A return or by-pass line24vis 'provided with the valve 2.

It will be readily understood that by placing on the damper s indleva cam in place of the usual straight ever, it wouldrbe possible to adjust my a iparatus in such a way as to maintain any i esired tiue gas composition.

lty will be apparent from the above descrip-v tion that ll have provided a control in which a temporary excess air supply is furnished simultaneously with an increase ot oil supply and that when the steam pressure goes down, the hy-pass pressure is increased furnishing more oil to the burner. More oil to the burner means that the ley-pass is closed and the ley-pass pressure increasing turnishes more air. ln other words the position ot' the damper is regulable by the bypass pressure.

lt will he further apparent that with an inn-ease ol steam pressure the oil supply to the atomizer 2O will decrease but the consequent diminution in the air supply is made to lag so that an adequate supply of air is ensured during the period ot change.

l wish it distinctly understood that my sysem ot' control may he adaptable to a straight mechanical atomizer without a return or hy-pass line by connecting the air control apparatus in the oil supply line so thai the pressure of the oil supply will operate it to regulate the air. While this will not give the wide range of control that my sysem applies to the Fisher-Peabody burners will, it is nevertheless Within the scope of my invention and ll therefore intend the following claims to cover such modifications.

ll claim:

l. An oil burning apparatus comprising an atomizer, means for delivering oil under pressure to said atomizer andl giving said oil a rotary motion, means for returning a portion oi said oil after. imparting to it said rotary motion, means for regulating the amount of oil returned, means for providing air for combustion and means for regulating amount ot' said air by the pressure of the oil returned.

2. A device as recited in claim 1`in which an excess supply of air is delivered during thedperiod of increase in amount of oil atomize 3. A device as recited in claim 1 with the addition of lneans for providing for an cxcess supply ot' air during the Aperiod of dccrease in amount of oil atomized.

4. A device as recited in claim 1 with the addition of means for providing for an excess supply of air during the period of increase in amount of oil atomized, and means tor providing for an excess supply of air during the period of decrease in amount of oil atomized.

5. A method of controlling the combustion ot' tuel in a boiler furnace which comprises delivering tuel under pressure to an atomizer, imparting rotary motion to Jthe fuel returning a regulable amount of fuel after imparting a rotary motion thereto, controlling the amount of fuel returned by the variation in steam pressure in the boiler, supplying air for combustion and co.itrol ling the amount of air supplied by the vpressure of the fuel returned.

t. A method for controlling the combustion of fuel in a furnace which comprises dclivering fuel under a uniform pressure to the point of combustion imparting a whirling motion thereto, returning a portion of the whirling fuel, controlling the amount of fuel returned in accordance with the variation in steam pressure, controlling the air supply by the pressure of the fuel returned, and providing an excess of air during the period of change from any working condition to another.

7. A method of producing heat by burning liquid fuel comprising the ,delivery of the fuel to an atomizer imparting a rotary motion to the fuel, providing air for combastion, controlling the amount of fuelatomized by returning from the atomizer a regulable portion ofthe liquid after imparting a. rotary motion thereto, regulating the amount returned to control the amountv of heat produced and regulating the amount of air by the pressure of fuel returned from the atomizer.

lln testimony whereof ll ax my signature.

LllUNlEL S. MARKS. 

